Traffic signal



March 7, 1933. 11 Q WLLER 1,900,723

TRAFFIC SIGNAL Filed April 21, 1930 6 7 hole 0. Miller Qfiorneg Patented Mar. 7-, 1933 DALE O. MILLER, OF

PATENT OFFICE DETROIT, MICHIGAN craArrrc srenu.

Application filed April 21,

This invention relates to traffic signals and is more particularly concerned with a trafiic lighting signal system wherein lights of different colors, such as green and red, are used for the purpose of directing traffic where roads or streetscross each other, the traffic being stopped when the red light signal shows and permitted to go on during the time that the green light signal shows.

10 Not infrequently a light bulb either for the green or red light burns out and as a result during a part ofthe time no light shows at all to guide the travel in one direction of movement while in the other direction of movement all of the lights both green and red operate the same as if all of the lights were in good condition. It is particularly dangerous in case the light bulb for a red light is burned out and no showing in one direction appears, but only an intermittent showing of the green light with a blank between in which no light is shown; yet in the other direction of trafiic movement both the green and red lights alternately show to the traific and a green light will appear while for the first trafiic direction of movement referred to at the same time no light will appear. In such case the traffic which, from the green light showing, has a clear road is very liable to pass by the road intersection without slowing up, putting faith upon the green light showing a clear road; yet on vfronting them. And in association with the the intersecting road there will be no red light, indicating that traflic should stop but only a blank unlighted surface, whereupon drivers of motor vehicles are very liable not to stop but will cross the line of traffic which has the right of way without sensing that the red light stop signal should be against them.

40 This has resulted in serious accidents in very many cases.

It is a primary object and purpose of the present invention to connect all of the red and green lights which signal fortrafiic control in all directions at a road intersection insuch a manned that if any one of the several light bulbs which are used should be burned out, all of the light bulbs for signal ing or controlling trafiic from all directions leading to the intersection thereafter will not 1930. Serial No. 445,903.

be lighted until the burned out bulb has been replaced. Under such circumstances, no signal operating at all at the intersection, traflic coming to the intersection moves cautiously and the danger of accident is greatly reduced. 5b

A further object of this invention is to provide automatic means for immediately breaking the electric circuits in which all of the green and red lights are located whenever a light bulb for any of the lights is burned out or otherwise becomes useless so that after the useless light bulb has been re-' placed it is necessary to manually reclose the circuits before the system will operate.

A still further object of the invention is to provide, in addition to the green and red lights, a series of amber lights associated With the green and red lights with suitable electric connections such that the amber lights flash on momentarily between changes from red to green and vice versa; and also provide the system with means operating automatically for turning electric current on and through the amber lights continuously when a light bulb, either green or red is burned out and all of the lights, green and red, are thereafter inoperative. This provides amber lights continuously lighted and visible from all directions of travel at a road intersection so that all Vehicles approaching the intersect-ion from all directions proceed cautiously by reason of the amber light indications conamber lights at the time that they are lighted continuously a warning signal, either an electric hell or a flood light may be brought into continuous operation to indicate that the lighting system is out of order and needs attention.

An understanding of the invention for the attainment of the ends stated and the constructions and lighting circuits which embody the same will be had from the following description taken in connection with the accompanying drawing, in which, 9

The figure is a diagrammatic illustration of the warning lighting system of my invention. e

In the construction and operation of the lighting system of the invention, two lights 100 1 and 1a, showing red when lighted may be placed in alinement and connected in series by the wire 2. The feed wire 3 carrying the electric current to the first light 1 joins with a winding 4 of a magnet coil while from the other end of the magnetic coil winding a Wire 5 leads to which a feed wire 6 from the source of electric energy, such as a main electric wire, is connected, as shown. Two

other red lights 7 and 8 connected in series by a wire 9 are associated with the lights 1 and 1a being disposed at right angles to the lights 1 and 1a as shown. A wire 10 connects the said wire 3 with the first light 7 of the two. A wire 11 leads from the second light 8 to the first light 12 of two green lights 12 and 13 connected in series by a wire 14. From the light 13 a wire 15 leads to a contact 16 as shown.

From the light 1a of the first two red lights described, a wire 17 leads to the first oftwo additional green lights 18 and 19 connected in series by the wire 20, the lights 18 and 19 being located at right angles to the two lights 12 and 13. From the second light 19 a wire 21 I leads to a second contact 16a located closely adjacent the contact 16 described. Associated with the contacts 16 and 164 are two complementary contacts 22 and 23 mounted so on a lever 24 which in turn is pivotally mount-.

ed to turn about a pivot 25 so that one end of the arm moves toward or away from the magnet core 4a. Wires 26 and 27, respectively, connect the contacts 22 and 23 with contacts 28 and 29 disposed on a support 30 so that they will be intermittently brought into electrical engagement with other contacts 31 and 32, respectively. disposed on a rotating cylinder drum 33. the bar support 30 being preferably disposed parallel to the axis of the drum. Wires 34 and 35. respectively, lead from the contacts 31 and 32 and connect to a wire 36 from which the negative 5 or outlet wire 37 of the main electric circuit leads.

With this construction when all the lights at 1. 1a 7 and 8. 12 and 13. and 18 and 19 are in operative condition and with the lever 24 magnetically held against the core 4a of the magnet, that is.-with the contacts 16 and 22 and 16m and 23 in. engagement, the electric current may pass through the wire 3 to the lights 1 and 1a thence through the wire 17 55 and thelights 18 and 19. through the wire 21 to the contacts 160. and 23 and through the wire 27 to contacts 29 and 32 and from the wire to the outgoing wire 37. Accordingly, when the two contacts 29 and 32 are in I engagement the two red lights 1 and 1a and the two green lights 1.8 and 19 will be lit, and as the red lights face in a direction at right angles to the green lights 18 and 19 the road from which the green lights 18 and 19 are ob-. servable will be free for traffic while the intersecting road will be controlled and traflic stopped by the red lights 1 and 1a.

With the rotation of the drum 33 contact 31 will be brought to the contact 28 a very short time, say two' seconds, before the contact 32 leaves the contact 29. As soon as contacts 28 and 31 engage the current passes through the wires 3 and 10 to light the red lights 7 and 8, then through the wire 11 to light the green lights 12 and 13, therefrom through the wire 15 to the contacts 16 and 22. thence through the wire 26 to the contacts 28 and 31 which are together, and therefrom through the wires 34 and 36 to the outgoing wire 37. The green lights 12 and 13 will open the previously closed road for traflic passage, while the red lights 7 and 8 will close the previously open road for trafiic.

It will be observed in all cases that there is no break occurring in the passage of current through the magnet coil 4 and that at no time are any of the circuits described as com- .pleted by the rotation of the switch drum 33 both broken at the same so that the bar 24 will always be held magnetically in the position shown in the drawing against the end of the core 4a.

If, however, when the contacts 29 and 32 I are brought together there is any break in the circuit by reason of a light, such as any one of the lights 1 and 1a, or 18 and 19, being burned out, and at the same time the contacts 28 and 31 are not in engagement, as soon as the circuit for the passage of electric current is broken, the magnet coil 4 has no current passing therethrough, the core 4a is deenergized and the bar or lever 24 drops away from the core 4a and separates contacts 22 and 23 from the contacts 16 and 16a respectively; whereupon with the continuation of the rotating movement of the drum 33, when the contacts 28 and 31 are brought together, the circuit in which they are located is broken between the contacts 16 and 22 and there is no lighting of any of the lights either those in the first circuit, such as the lights 1,10, 18 and 19 or in the second circuit 7 and 8, 12 and 13.

Accordingly, the burning out of any light 1, 1a, 18 or 19 automatically renders it impossible to light any of the green or red lights. If the burning out of a light bulb in the circuit containing the lights 7 and 8 and 12 and 13 should occur, "a like break in the continuity of the passage of the electric current of the coil 4 will take place and the bar 24 will drop down so as to separate the contacts at 16 and 16a thereby breaking all of the circuits which contain the green and red lights.

In order to put the system-back in operative condition the light which has been burned out or otherwise rendered useless so as to break the circuit in which it is located must be replaced and, furthermore, the lever or bar 24 manually moved so as to bring contacts 22 and 23 thereon into electric connection with the contacts 16 and 16a.

The system thus far described is operative and workable without anything further added thereto. As a desirable auxiliary it is designed that four amber colored lights shall be used which flash for a limited period of time between consecutive red to green or green to red in controlling the traflic on the different roads leading to the road intersection. These amber lights will be lighted for ashort period of time before the contacts 29 and 32 separate and for a short period of time after the contacts 28 and 31 are brought together and vice versa. There are four of the amber lights 38, two of them disposed at right angles to the other two and connected in series with the wire 5 as shown, having leading from the last light of the series a wire 39 which leads to a contact 40 disposed above but normally separated from a third contact 41 on the end of the lever or bar 24. A wire 42 leads from the wire 39 before it reaches the contact 40 to a third contact 43 on the supporting bar 30 to which a contact 44 on the drum 33 periodically comes. A wire 45 leads from the contact 44 to the wire 36 previously described.

Between the wires 39 and 5, as shown, a connecting wire 46 is disposed in which a signal light or its equivalent, a signal bell 47 may be interposed so as to light or ring at the time that the amber lights 38 are lit; and when the amber lights are lit continuously as described the signal at 47 will show or sound continuously.

It will be noted that in all of the circuits described there are four light bulbs in series. The usual voltage of the electric light circuits in the United States is 110 volts and if 110 volt light bulbs are used it will be necessary to step up the voltage to 440 volts by use of a suitable transformer; However, lighting bulbs with circuits to carry 27% volt current are obtainable in most places and with four of such bulbs in a series it is not necessary to change the regular 110 volt lighting circuit by using a transformer.

The construction and system described is very practical and useful. The system now in common use, subject to the defects noted, can be very quickly and easily changed over to the system and construction of my invention at very little expense. The increase in safety of travel on the road intersections where travel is heavy is a very valuable fea ture of my invention. This follows from the automatic inoperativeness of all the green and red light bulbs visible fromall directions of travel leading to the road intersection when any green or red light becomes burned out so as to place drivers under the necessity of caution in approaching the intersections. This occurs irrespective of whether or not the amber light auxiliary to the invention is used, and of course with the amber lights used such lights themselves warn all drivers to approach and take the crossing at the road intersection with caution. At no time will there be a green light indication causing drivers to think that the road is free and open while at the same time from a failure of red lights for the intersecting road drivers thereon are led to believe that the intersection may be crossed on the basis that the entire signal light system is not in operation. If one light, either green or red, is burned out all lights both green and red become inoperative and the amber colored lights become continuously operative. The invention is defined in the appended claims and is to be con-' sidered comprehensive of all forms of structures coming within their scope.

I claim:

1. In a lighting system, two electric lights of one color, two additional electric lights of a different color, an electric light wiring circuit in which all of said lights are connected in series, a second electric wiring circuit including two pairs of electric lights all of the lights being connected in series in said second circuit and the two pairs of electric lights in said second circuit being of different colors and located at right angles to the two pairs of electric lights in the first circuit, means for alternately-completing the two wiring circuits and means for automatically breaking both circuits when any one of the four pairs of lights is burned out.

2. In a signaling system, four-lights of all the same color located in pairs at right angles to each other, the light of each pair being 2 connected in series, two electric wiring circuits in which said pairs of lights are included, an additional two pair of lights of a different color located substantially at right angles to each other, each pair being connected in series and one pair of each of said lastmentioned pairs of lights being in each of said wiring circuits, a pivotally mounted lever, two contacts thereon, cooperating contacts with which the wires of said two wiring circuits connect, means for alternately opening and completing the two circuits, one circuit not being opened until the other has been completed and vice versa, an electro magnetic means for normally holding said lever in a position to keep said contacts together but automatically releasing when either of said circuits is broken thereby breaking both circuits to extinguish lights in the two circuits.

3. A construction containing the elements in combination defined in claim 2, combined with four additional electric lights all of the same color and differing in color from all "of the rest of the lights, a third electric circuit in which said additional lights are connected in series, and means for automatically completing the third circuit when said lever is released from the electro magnetic means holding it in normal position, whereby all of the four lights of the third series of lights are continuously lighted when the other lights are all inoperative.

4. A 'gnaling device of the character described comprising,-two signals adapted to appear from different directions, a single means for alternately operating the signals and means associated with said operating means for causing said operating means to become inefi'ective upon failure of either of said signals to operate.

5. A signaling device comprising two signals, an electric device for actuating each signal, an electric circuit for each electric device, said circuits having a common feed Wire and separate return wires, means for closing both circuits in their respective re-' turn wires, means actuated by current in the common feed wire for holding said circuit closing means in closed position, said circuit closer means being arranged to automatically open said circuits upon cessation of flow of current through said feed wire and means for closing the circuit in each of said return wires during intermittent and opposite periods. said circuit closer acting to close the circuit in one return wire before opening it in the other and vice versa.

6. In,a lighting system, two lights or the ke, two circuits in which said lights are located. a pivotally mounted lever, tWo contacts thereon, co-operating contacts with which the wires of said two wiring circuits connect, means for alternately opening and completing the two circuits, one circuit notbeing broken until the other has been completed and vice versa, an electromagnetic means for normally holding said lever in a position to keep said contacts together but automatically releasing when either of said circuits is broken bv a light burning out,

therebv breaking both circuits to extinguish li hts in the two circuits.

7. In a signaling svstem of the class described. two lights of the same color, said lights being located so as to be visible from points on the axes substantially at right angles to each other. two electric wiring circuits in which said lights are included, an additional set of two lights of a different color located substantiallv at' right angles to each other similarlv to the first mentioned two lights, said additional set of lights being located one in each of the previously mentioned two electric wiring circuits, movable means. two contacts thereon. cooperating contacts with which the wires of said two Wiring circuits connect, means for alternately openmg and completing the two circuits, one circuit not being opened until the other has been completed and vice versa, means for normally holding said movable means in a position to keep said contacts together but automatically releasing when either of said circuits is broken thereby breaking both circuits to extinguish lights in the two circuits.

8. A construction containing the elements in combination defined in claim 7 combined with one additional electric light of the same color and differing in color from all of the rest of the lights, a third electric circuit in which said light is located, and means for completing the third circuit when said movable means is released from the means holding it in normal position, whereby the one additional light is continuously lighted when the other lights are all inoperative.

9. In a device of the character described,

a plurality of electric circuits, signals, signal operating means in each of said circuits, means for alternately energizing said circuits whereby said signals are alternately displayed, and means for rendering the second named means inoperativeto energize any of saidcircuits when anyone of said circuits is incapable of being energized due to a fault therein.

In testimony whereof I afiix my signature.

DALE O. MILLER. 

